• Journal of Advanced Marine Engineering and Technology
• /
• 제38권1호
• /
• pp.48-55
• /
• 2014

UV 발생용 플래시램프의 전원공급장치는 강력한 아크방전을 유발하기 위하여 높은 승압 비를 갖는 전압변환회로를 가지고 있다. 일반적인 구조는 높은 승압비의 트랜스포머와 배전압정류방식(코크라프트 올튼 회로 등)으로 방전관의 절연을 파괴함과 동시에 방전관에 전류를 급격히 통과시키는 방식으로 구동한다. 이 때, 제논방전관의 방전특성상 입력전류를 제한하지 않으면 방전관의 과다 발열, 전극손실, 봉입기체의 산화가속 등으로 수명저하의 원인이 되므로, 반드시 방전관에 유입되는 전류를 제한해야 되며, 이를 Ballast라 하는데 일반적으로 인덕터나 저항을 사용하여 인입전류량을 제한한다. 트랜스포머의 자가 공진(self-resonance)을 이용하면 낮은 1, 2차권선 비에도 고유주파수의 전후에서 비교적 높은 피크 전압을 얻을 수 있다. 또한 트랜스포머의 특정주파수에서 고유임피던스 성분을 이용하여 출력전압을 필터링하면 제논방전관이 자가 발진방식으로 동작하므로 종래의 회로구성보다 간단하고 경제적인 아크방전 파워 스테이지의 구성이 가능하다.

• 한국광학회:학술대회논문집
• /
• 한국광학회 2004년도 제15회 정기총회 및 동계학술발표회
• /
• pp.86-87
• /
• 2004

• 대한전기학회논문지:시스템및제어부문D
• /
• 제51권12호
• /
• pp.542-548
• /
• 2002

We consider an unknown linear time invariant plan with static load disturbance. A saturation function nonlinear element is sued to find th one point information in the frequency domain. We analyze an asymmetric self-oscillation caused by static load disturbance with relay feedback and saturation function feedback. We propose a new method to tune a PID controller using a saturation nonlinear feedback element in the presence of asymmetric oscillation. The proposed method does not require the knowledge of plant d.c. gain with an asymmetric oscillation in the plat output.

• 한국광학회:학술대회논문집
• /
• 한국광학회 1990년도 제5회 파동 및 레이저 학술발표회 5th Conference on Waves and lasers 논문집 - 한국광학회
• /
• pp.73-78
• /
• 1990

1.3${\mu}{\textrm}{m}$ DFB with absorption grating of 1.55${\mu}{\textrm}{m}$ InGaAsP layer was fabricated. This new type of DFB laser shows self-plusation for DC operation. At low level of injection the relation between the pulsation frequency and the injection current shows similar behavior with the relaxation oscillation of ordinary laser and at high level of injection the pulsation frequency decreases compared to the relaxation oscillation. Period doubling, period 3 and 4 were observed for AC modulation. In case of period doubling the waveform shows only one pulse within a period without any accompanying subsidiary pulses and the oscillation frequency was quite stable. The pulse widths as short as 58.5 ps was achieved with AC modulation. We propose the time division multiplexing application of this kind of DFB laser.

• International Journal of Control, Automation, and Systems
• /
• 제5권1호
• /
• pp.35-42
• /
• 2007

This paper presents an INS(Inertial Navigation System) grade, surface micro-machined differential resonant accelerometer(DRXL) manufactured by an epitaxially grown thick poly silicon process. The proposed DRXL system generates a differential digital output upon an applied acceleration, in which frequency transition is measured due to gap dependent electrical stiffness change. To facilitate the resonance dynamics of the electromechanical system, the micromachined DRXL device is packaged by using the wafer level vacuum sealing process. To test the DRXL performance, a nonlinear self-oscillation loop is designed based on the extended describing function technique. The oscillation loop is implemented using discrete electronic elements including precision charge amplifier and hard feedback nonlinearity. The performance test of the DRXL system shows that the sensitivity of the accelerometer is 24 Hz/g and its long term bias stability is about 2 mg($1{\sigma}$) with dynamic range of ${\sigma}70g$.

• 센서학회지
• /
• 제21권3호
• /
• pp.235-239
• /
• 2012

This paper presents frequency response compensation technique, and a self-oscillation circuit for capacitive microresonator with the compensation technique using programmable capacitor array, to compensate for the frequency response distorted by parasitic capacitances, and to obtain stable oscillation condition. The parasitic capacitances between the actuation input port and capacitive output port distort the frequency response of the microresonator. The distorted non-ideal frequency response can be compensated using two programmable capacitor arrays, which are connected between anti-phased actuation input port and capacitive output port. The simulation model includes the whole microresonator system, which consists of mechanical structure, transimpedance amplifier with automatic gain control, actuation driver and compensation circuit. The compensation operation and oscillation output of the system is verified with the simulation results.

• 대한전기학회:학술대회논문집
• /
• 대한전기학회 1999년도 하계학술대회 논문집 F
• /
• pp.2505-2507
• /
• 1999

This paper presents novel self excited DC-DC converters such as Buck-boost type, Buck type and also non-inverting Buck-boost type. The proposed converters has the following advantages: simple topology, small number of circuit components, easy control methode. Therefore, these converters are suitable for the portable appliances with battery source. Theoretical analysis and experimental results for SOW class Buck-boost type self oscillation DC-DC converter have been obtained, which demonstrate the high efficiency and good performance.

• 한국연소학회:학술대회논문집
• /
• 한국연소학회 2012년도 제44회 KOSCO SYMPOSIUM 초록집
• /
• pp.83-85
• /
• 2012

Experimental study in coflow jet flames has been conducted to investigate the effects of adding $N_2$, $CO_2$ and He to coflowing air-side in self-excitations. Differences in the behaviors between buoyancy-driven and diffusive-thermal self-excitations with similar frequency range are explored and discussed in laminar coflow jet flames.

• 한국추진공학회지
• /
• 제14권5호
• /
• pp.92-100
• /
• 2010

75톤급 기술검증용 연소기의 연소안정성 시험이 저압 조건에서 수행되었다. 이 시험에 사용된 두 개의 연소기 헤드 중 하나는 631개의 분사기를 가지며, 다른 하나는 721개의 분사기를 가진다. 631개의 분사기를 갖는 연소기 헤드는 연소압력 30 bar에서 자발 불안정이 발생하였고 721개의 분사기를 갖는 연소기 헤드는 동일한 연소압력과 동일한 유량 조건에서 고주파 연소안정성이 유지됨을 보였다. 그러나 721개의 분사기를 갖는 연소기 헤드는 연소압력 20 bar에서 자발 불안정이 발생하였고 이러한 결과로부터 연소기 헤드의 형상은 안정성 경계 영역을 변화시킴을 알 수 있었다.

• 한국조명전기설비학회:학술대회논문집
• /
• 한국조명전기설비학회 2004년도 학술대회 논문집
• /
• pp.175-178
• /
• 2004

Power supply technique for electrodeless lamps, especially self-oscillation method, is presented in this paper for Endura of Osram. The power supply uses different method for high efficiency at high frequency operation compared to the conventional method using saturable transformer. Exact parameter tuning using simulation is suggested for effective design for real applications.